The configuration of such a puncture needle cartridge and a puncture instrument using it would conventionally be as follows. That is, a puncture needle cartridge would comprise: a columnar lancet body having a puncture needle on the front end side and a puncture instrument mount on the rear end side; and a protective cap covering the tip of the puncture needle and being provided with an operation part on the front end side. The rear end side of the protective cap would be configured to be coupled to the lancet body via a separating part (e.g. Patent Document 1).